I use the sportster replay and I recenlty installed the fm modle relay
Buy the SIRIUS FM Module Relay (DEI 14110) and other Satellite Radio Portable Accessories at circuitcity.com
It provides a hardwire connection to you factory stereo and since it is a relay it cuts-out the standard fm antenna for your truck when you satellite is powered on this eliminating any interference. The sound quality is damn good too. I could barely tell the difference between it and a usa-spec adapter. Plus, its alot cheaper than some of the other products.